Embodiments described herein relate generally to the preparation of electrodes for use in electrochemical devices and more particularly to systems and methods of using a semi-solid electrode having a porous current collector.
A conventional rechargeable battery normally has a negative electrode comprising an active material which releases ions (e.g., lithium ions in Li-ion batteries) when discharging and intercalates or absorbs ions when the battery is being charged. The positive electrode of the battery can comprise an active material that is capable of reacting with the ions on discharge, and releasing the ions on charging the battery. In some batteries, the negative electrode is separated from the positive electrode by a separator, which is permeable to ionic flow but can prevent electric contact between the two electrodes. In order to have a high capacity, the active materials are normally a thick layer of particulate paste, and the electronic conductivity can be low. Therefore, a current collector is typically used to provide a conducting path through the paste and thereby reduce the resistance of the battery. The current collector can also act as a physical support for the active materials which otherwise would be a brittle structure. Conventional batteries also include an ion containing electrolyte, which may be either a non-aqueous liquid or a solid organic polymer and allows the flow of electrical charge between the two electrodes.